// import java.io.*;
public class crc {

    // Compute a correct-endian (little) CRC using.
    // We don't use the java.utils.zip.crc because it is an opaque
    // implementation and we need one we can replicate in lisp.

    public static int INITIAL_CRC = 0x00B704CE; 

    static int crctable [] = {
		  0x000000, 0x864cfb, 0x8ad50d, 0x0c99f6, 0x93e6e1, 0x15aa1a, 0x1933ec, 0x9f7f17, 
		  0xa18139, 0x27cdc2, 0x2b5434, 0xad18cf, 0x3267d8, 0xb42b23, 0xb8b2d5, 0x3efe2e, 
		  0xc54e89, 0x430272, 0x4f9b84, 0xc9d77f, 0x56a868, 0xd0e493, 0xdc7d65, 0x5a319e, 
		  0x64cfb0, 0xe2834b, 0xee1abd, 0x685646, 0xf72951, 0x7165aa, 0x7dfc5c, 0xfbb0a7, 
		  0x0cd1e9, 0x8a9d12, 0x8604e4, 0x00481f, 0x9f3708, 0x197bf3, 0x15e205, 0x93aefe, 
		  0xad50d0, 0x2b1c2b, 0x2785dd, 0xa1c926, 0x3eb631, 0xb8faca, 0xb4633c, 0x322fc7, 
		  0xc99f60, 0x4fd39b, 0x434a6d, 0xc50696, 0x5a7981, 0xdc357a, 0xd0ac8c, 0x56e077, 
		  0x681e59, 0xee52a2, 0xe2cb54, 0x6487af, 0xfbf8b8, 0x7db443, 0x712db5, 0xf7614e, 
		  0x19a3d2, 0x9fef29, 0x9376df, 0x153a24, 0x8a4533, 0x0c09c8, 0x00903e, 0x86dcc5, 
		  0xb822eb, 0x3e6e10, 0x32f7e6, 0xb4bb1d, 0x2bc40a, 0xad88f1, 0xa11107, 0x275dfc, 
		  0xdced5b, 0x5aa1a0, 0x563856, 0xd074ad, 0x4f0bba, 0xc94741, 0xc5deb7, 0x43924c, 
		  0x7d6c62, 0xfb2099, 0xf7b96f, 0x71f594, 0xee8a83, 0x68c678, 0x645f8e, 0xe21375, 
		  0x15723b, 0x933ec0, 0x9fa736, 0x19ebcd, 0x8694da, 0x00d821, 0x0c41d7, 0x8a0d2c, 
		  0xb4f302, 0x32bff9, 0x3e260f, 0xb86af4, 0x2715e3, 0xa15918, 0xadc0ee, 0x2b8c15, 
		  0xd03cb2, 0x567049, 0x5ae9bf, 0xdca544, 0x43da53, 0xc596a8, 0xc90f5e, 0x4f43a5, 
		  0x71bd8b, 0xf7f170, 0xfb6886, 0x7d247d, 0xe25b6a, 0x641791, 0x688e67, 0xeec29c, 
		  0x3347a4, 0xb50b5f, 0xb992a9, 0x3fde52, 0xa0a145, 0x26edbe, 0x2a7448, 0xac38b3, 
		  0x92c69d, 0x148a66, 0x181390, 0x9e5f6b, 0x01207c, 0x876c87, 0x8bf571, 0x0db98a, 
		  0xf6092d, 0x7045d6, 0x7cdc20, 0xfa90db, 0x65efcc, 0xe3a337, 0xef3ac1, 0x69763a, 
		  0x578814, 0xd1c4ef, 0xdd5d19, 0x5b11e2, 0xc46ef5, 0x42220e, 0x4ebbf8, 0xc8f703, 
		  0x3f964d, 0xb9dab6, 0xb54340, 0x330fbb, 0xac70ac, 0x2a3c57, 0x26a5a1, 0xa0e95a, 
		  0x9e1774, 0x185b8f, 0x14c279, 0x928e82, 0x0df195, 0x8bbd6e, 0x872498, 0x016863, 
		  0xfad8c4, 0x7c943f, 0x700dc9, 0xf64132, 0x693e25, 0xef72de, 0xe3eb28, 0x65a7d3, 
		  0x5b59fd, 0xdd1506, 0xd18cf0, 0x57c00b, 0xc8bf1c, 0x4ef3e7, 0x426a11, 0xc426ea, 
		  0x2ae476, 0xaca88d, 0xa0317b, 0x267d80, 0xb90297, 0x3f4e6c, 0x33d79a, 0xb59b61, 
		  0x8b654f, 0x0d29b4, 0x01b042, 0x87fcb9, 0x1883ae, 0x9ecf55, 0x9256a3, 0x141a58, 
		  0xefaaff, 0x69e604, 0x657ff2, 0xe33309, 0x7c4c1e, 0xfa00e5, 0xf69913, 0x70d5e8, 
		  0x4e2bc6, 0xc8673d, 0xc4fecb, 0x42b230, 0xddcd27, 0x5b81dc, 0x57182a, 0xd154d1, 
		  0x26359f, 0xa07964, 0xace092, 0x2aac69, 0xb5d37e, 0x339f85, 0x3f0673, 0xb94a88, 
		  0x87b4a6, 0x01f85d, 0x0d61ab, 0x8b2d50, 0x145247, 0x921ebc, 0x9e874a, 0x18cbb1, 
		  0xe37b16, 0x6537ed, 0x69ae1b, 0xefe2e0, 0x709df7, 0xf6d10c, 0xfa48fa, 0x7c0401, 
		  0x42fa2f, 0xc4b6d4, 0xc82f22, 0x4e63d9, 0xd11cce, 0x575035, 0x5bc9c3, 0xdd8538 
    };

    static int byte_to_unsigned_int (byte b) {
	return (b < 0)
	    ? (int)b + 256
	    : (int)b;
    }

//     static long int_to_unsigned_long (int i) {
// 	return (i < 0)
// 	    ? (long)i + 4294967296L
// 	    : (long)i;
//     }

  private static long int_to_unsigned_long (int i)
  {
      // Convert a signed integer to an unsigned long by 2's complement operation if necessary.
      // This allows us to avoid sign-extension problems.

      return (i < 0)
	  ? (long)i + 4294967296L // (expt 2 32)
	  : (long)i;
  }

    static int update_crc (int current_crc, byte bytes[], int count) {
	int index = 0;
	int crc = current_crc;
	while (index < count) {
	    crc = ((crc & 0x00007FFF) << 8) 
		^ crctable [byte_to_unsigned_int (bytes[index]) ^ ((crc >> 16) & 0xFF)];
	    index += 1;
	    };
	return crc;
    }

//     public static void main (String argv []) 
//     {
// 	try {
// 	    FileInputStream instream = new FileInputStream (argv [0]);
// 	    byte buffer [] = new byte [4096];
// 	    int crc = INITIAL_CRC;
// 	    int count = 0;

// 	    while (true) {
// 		count = instream.read (buffer);
// 		if (count == -1) break;
// 		crc = update_crc (crc, buffer, count);
// 	    };

// 	    System.out.println ("CRC of \"" + argv[0] + "\" is " + int_to_unsigned_long (crc));
// 	}
// 	catch (Exception e) {
// 	    System.out.println ("Didn't work." + e);
// 	}
//     }
}
